At first glance surfboards look simple but designing a high performing board of predictable performance is a difficult task. This is not only because the board interacts with water flows on the face of a wave close to breaking, making water flow along and around them very complex, but the rider and today's competitions demand high speed, quick turning, and manoeuvres where the board leaves the wave face at one point and rejoins it at another. The board is highly and unpredictably stressed, while it is being directed to perform these manoeuvres. The board is constantly undergoing changing and reversing bending and twist forces while the rider relies on it for his or her safety when riding a wave which is also unpredictable and powerful.
The largest portion of a surfboard by volume is a buoyant block, which, before it is formed into a board, is called a blank and it is usually made of foam. Most often the blank includes a stringer, which is a structural member such as a long beam of balsa or other wood, normally extending along a fore-and-aft midline of the board and glued to both halves of the blank.
To shape the blank, first, a rough outline of a desired board shape is cut from the blank and that outline is machine and hand planed and then sanded. The shaper pays close attention to various characteristics known to affect turning, stability, reliability and speed, including rocker (built-in upward bend) of various sections of the blank, rail or edge sharpness at various points along the blank, tail volume and shape, and rail plan radius along the blank. The shaped blank is then coated with various layers, finishing with a glass fabric layer covered with resin for structural support.
However, because of the large, constantly varying and reversing bending and twisting stresses in the board, known board structures have limitations. Boards can flex unduly and may often break and in other aspects do not provide the performance demanded by skilled riders and spectators.
The present invention provides a new surfboard with useful performance characteristics.
Any reference to or discussion of any document, act or item of knowledge in this specification is included solely for the purpose of providing a context for the present invention. It is not suggested or represented that any of these matters or any combination thereof formed at the priority date part of the common general knowledge, or was known to be relevant to an attempt to solve any problem with which this specification is concerned.